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Hey guy., check out this question!!!

Looking at a project, project includes change butterfly Nd new pump,
Instead of draining building, I heard of a practice that freezes the pipe for a few hours to be able to change valves., awesome .
What u guys think?

"You will encounter many distractions and many temptations to put your goals aside: The security of a job, a wife who wants kids, Whatever. But if you hang in there, always following your vision, I have no doubt you will succeed.
Larry Flynt quote

It works great but isn't cheap on large diameter pipe. You can buy a kit for small dia pipe (under 3/4") for about $500 and do it yourself. There's companies that specializing in pipe freezing for large dia pipe.

I have frozen pipes the biggest being 6" using a rig we made at the shop and getting dewars of liquid nitrogen. If you wanna see some pics ill send some to you but it wont be until monday

Basically I took and 8" 18" long peice of pipe welded flat plate on each end cut a 6" hole in both ends. Then I cut that down the middle put flanges on it so it could be bolted back together to wrap arounf the pipe. use a weldolet to hook a hose with a valve on it to hook to the dewar of LN and have an exhaust port on the other end. then you put some temp probes in the collar you made and start bleeding the LN into the collar as it boils it off it will get cold quick down around -200 or colder you have to moniter the temp regular basiclly one man just for this. Ice plug complete

we have the setup, we used it on domestic water supplies more often than hvac we did a 20" line feeding a paper plant and the incoming pressure was 60 psi and live. the city couldnt shut down water for two months sinceit was an industrial site and everyone else needed wqater
we have our own setup but we rented two more so we froze the same line at three spots for safety reasons .
all of these ran off liquid co2 and we had so many tanksnit was comical. we had 8 guys workimg that weekend